CREATE CONTROLFILE

Caution: Oracle recommends that you perform a full backup of all files in the database before using this statement. For more information, see Oracle8i Backup and Recovery Guide.

Purpose

Use the CREATECONTROLFILE statement to re-create a control file in one of the following cases:

All copies of your existing control files have been lost through media failure.

You want to change the name of the database.

You want to change the maximum number of redo log file groups, redo log file members, archived redo log files, datafiles, or instances that can concurrently have the database mounted and open.

When you issue a CREATECONTROLFILE statement, Oracle creates a new control file based on the information you specify in the statement. If you omit any clauses, Oracle uses the default values rather than the values for the previous control file. After successfully creating the control file, Oracle mounts the database in the mode specified by the initialization parameter PARALLEL_SERVER. You then must perform media recovery before opening the database. It is recommended that you then shut down the instance and take a full backup of all files in the database.

Prerequisites

You must have the OSDBA role enabled. The database must not be mounted by any instance.

If the REMOTE_LOGIN_PASSWORDFILE initialization parameter is set to exclusive, Oracle returns an error when you attempt to re-create the control file. To avoid this message, either set the parameter to shared, or re-create your password file before re-creating the control file.

See Also: Oracle8i Reference for more information about the REMOTE_LOGIN_PASSWORDFILE parameter

Syntax

logfile_clause::=

datafile_clause::=

character_set_clause::=

filespec: See filespec.

Keywords and Parameters

REUSE

Specify REUSE to indicate that existing control files identified by the initialization parameter CONTROL_FILES can be reused, thus ignoring and overwriting any information they may currently contain. If you omit this clause and any of these control files already exists, Oracle returns an error.

DATABASEdatabase

Specify the name of the database. The value of this parameter must be the existing database name established by the previous CREATEDATABASE statement or CREATECONTROLFILE statement.

SETDATABASEdatabase

Use SETDATABASE to change the name of the database. The name of a database can be as long as eight bytes.

logfile_clause

LOGFILEfilespec

Specify the redo log files for your database. You must list all members of all redo log file groups.

See Also: filespec for the syntax of filespec

GROUPinteger

Specify the logfile group number. If you specify GROUP values, Oracle verifies these values with the GROUP values when the database was last open.

RESETLOGS

Specify RESETLOGS if you want Oracle to ignore the contents of the files listed in the LOGFILE clause. These files do not have to exist. Each filespec in the LOGFILE clause must specify the SIZE parameter. Oracle assigns all online redo log file groups to thread 1 and enables this thread for public use by any instance. After using this clause, you must open the database using the RESETLOGS clause of the ALTERDATABASE statement.

NORESETLOGS

Specify NORESETLOGS if you want Oracle to use all files in the LOGFILE clause as they were when the database was last open. These files must exist and must be the current online redo log files rather than restored backups. Oracle reassigns the redo log file groups to the threads to which they were previously assigned and reenables the threads as they were previously enabled.

datafile_clause

DATAFILEfilespec

Specify the datafiles of the database. You must list all datafiles. These files must all exist, although they may be restored backups that require media recovery. See the syntax description of filespec in filespec.

MAXLOGFILESinteger

Specify the maximum number of online redo log file groups that can ever be created for the database. Oracle uses this value to determine how much space in the control file to allocate for the names of redo log files. The default and maximum values depend on your operating system. The value that you specify should not be less than the greatest GROUP value for any redo log file group.

MAXLOGMEMBERSinteger

Specify the maximum number of members, or identical copies, for a redo log file group. Oracle uses this value to determine how much space in the control file to allocate for the names of redo log files. The minimum value is 1. The maximum and default values depend on your operating system.

MAXLOGHISTORYinteger

Specify the maximum number of archived redo log file groups for automatic media recovery of the Oracle Parallel Server. Oracle uses this value to determine how much space in the control file to allocate for the names of archived redo log files. The minimum value is 0. The default value is a multiple of the MAXINSTANCES value and depends on your operating system. The maximum value is limited only by the maximum size of the control file. This parameter is useful only if you are using Oracle with the Parallel Server option in both parallel mode and archivelog mode.

MAXDATAFILESinteger

Specify the initial sizing of the datafiles section of the control file at CREATEDATABASE or CREATECONTROLFILE time. An attempt to add a file whose number is greater than MAXDATAFILES, but less than or equal to DB_FILES, causes the Oracle control file to expand automatically so that the datafiles section can accommodate more files.

The number of datafiles accessible to your instance is also limited by the initialization parameter DB_FILES.

MAXINSTANCESinteger

Specify the maximum number of instances that can simultaneously have the database mounted and open. This value takes precedence over the value of the initialization parameter INSTANCES. The minimum value is 1. The maximum and default values depend on your operating system.

ARCHIVELOG

Specify ARCHIVELOG to archive the contents of redo log files before reusing them. This clause prepares for the possibility of media recovery as well as instance or crash recovery.

NOARCHIVELOG

If you omit both the ARCHIVELOG clause and NOARCHIVELOG clause, Oracle chooses NOARCHIVELOG mode by default. After creating the control file, you can change between ARCHIVELOG mode and NOARCHIVELOG mode with the ALTERDATABASE statement.

character_set_clause

If you specify a character set, Oracle reconstructs character set information in the control file. In case media recovery of the database is required, this information will be available before the database is open, so that tablespace names can be correctly interpreted during recovery. This clause is useful only if you are using a character set other than the default US7ASCII.

If you are re-creating your control file and you are using Recovery Manager for tablespace recovery, and if you specify a different character set from the one stored in the data dictionary, then tablespace recovery will not succeed. (However, at database open, the control file character set will be updated with the correct character set from the data dictionary.)

Note: You cannot modify the character set of the database with this clause.